Genome Sequencing and Annotation of Sweetpotato Wild Progenitors

Sweetpotato, Ipomoea batatas, is among the most important food crops in the world and an extremely important food crop for subsistence farmers in sub-Saharan Africa. Despite its significant importance, currently the genomic resources for sweetpotato are very limited. Sweetpotato is an allo-auto-hexaploid (2n=6x=90) with two hypothesized, non-homologous genomes. The polyploid and heterozygous nature of the sweetpotato genome makes genetic and functional analyses extremely challenging. To facilitate research and breeding in this important species, we have assembled the genomes of I. trifida and I. triloba, two diploid wild progenitors of sweetpotato, using the Illumina and PacBio sequence reads. Both assembled genomes were ~460 Mb, ~87% and 90% of the I. trifida and I. triloba genomes with estimated sizes of 530 Mb and 510 Mb, respectively. The N50 sizes of the assembled scaffolds are 1.48 Mb and 6.46 Mb for I. trifida and I. triloba, respectively. High throughput transcriptome sequences have been generated from various different tissues and are being used to facilitate genome annotation. High-density genetic maps and BioNano physical genome maps are also being constructed for anchoring and ordering assembled genome scaffolds. The high-quality I. trifida and I. triloba genomes will serve as valuable references for extensive QTL mapping, marker identification and comparative genomics of sweetpotato.